My system has hit the same bug and I do not use firewire. I have not upgraded to mainline kernel. The power cycling work arounds above do not mitigate the issue for me.
$ cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=20.04 DISTRIB_CODENAME=focal DISTRIB_DESCRIPTION="Ubuntu 20.04 LTS" $ uname -a Linux hostname 5.4.0-39-generic #43-Ubuntu SMP Fri Jun 19 10:28:31 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux $ pactl info Connection failure: Connection refused pa_context_connect() failed: Connection refused $ ps aux | grep pulse | grep -v grep username 12895 17.0 0.0 100788 10908 ? D<s 09:38 0:00 /usr/bin/pulseaudio --daemonize=no --log-target=journal $ sudo cat /proc/12895/stack [<0>] usb_start_wait_urb+0x8f/0x180 [<0>] usb_control_msg+0xe3/0x140 [<0>] snd_usb_ctl_msg+0xe3/0x190 [snd_usb_audio] [<0>] snd_usb_init_sample_rate+0x235/0x320 [snd_usb_audio] [<0>] snd_usb_pcm_prepare+0x159/0x460 [snd_usb_audio] [<0>] snd_pcm_do_prepare+0x1e/0x30 [snd_pcm] [<0>] snd_pcm_action_single+0x3c/0x80 [snd_pcm] [<0>] snd_pcm_action_nonatomic+0x6e/0x80 [snd_pcm] [<0>] snd_pcm_prepare+0x6a/0x90 [snd_pcm] [<0>] snd_pcm_common_ioctl+0x28c/0xc00 [snd_pcm] [<0>] snd_pcm_ioctl+0x27/0x40 [snd_pcm] [<0>] do_vfs_ioctl+0x407/0x670 [<0>] ksys_ioctl+0x67/0x90 [<0>] __x64_sys_ioctl+0x1a/0x20 [<0>] do_syscall_64+0x57/0x190 [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 The stack frames line up w/ the above. $ journalctl -f | grep pulse # a selection of the output Jun 27 09:38:50 hostname systemd[2373]: pulseaudio.service: State 'stop-sigterm' timed out. Killing. Jun 27 09:38:50 hostname systemd[2373]: pulseaudio.service: Killing process 12140 (pulseaudio) with signal SIGKILL. Jun 27 09:38:56 hostname systemd[2373]: pulseaudio.service: Main process exited, code=killed, status=9/KILL Jun 27 09:38:56 hostname systemd[2373]: pulseaudio.service: Failed with result 'timeout'. Jun 27 09:38:56 hostname systemd[2373]: pulseaudio.service: Scheduled restart job, restart counter is at 5. Jun 27 09:38:56 hostname pulseaudio[12895]: Stale PID file, overwriting. Jun 27 09:40:26 hostname systemd[2373]: pulseaudio.service: start operation timed out. Terminating. Jun 27 09:41:56 hostname systemd[2373]: pulseaudio.service: State 'stop-sigterm' timed out. Killing. Jun 27 09:41:56 hostname systemd[2373]: pulseaudio.service: Killing process 12895 (pulseaudio) with signal SIGKILL. Jun 27 09:42:02 hostname systemd[2373]: pulseaudio.service: Main process exited, code=killed, status=9/KILL Jun 27 09:42:02 hostname systemd[2373]: pulseaudio.service: Failed with result 'timeout'. Jun 27 09:42:02 hostname systemd[2373]: pulseaudio.service: Scheduled restart job, restart counter is at 6. Jun 27 09:42:03 hostname pulseaudio[13050]: Stale PID file, overwriting. Jun 27 09:43:33 hostname systemd[2373]: pulseaudio.service: start operation timed out. Terminating. Jun 27 09:45:03 hostname systemd[2373]: pulseaudio.service: State 'stop-sigterm' timed out. Killing. Jun 27 09:45:03 hostname systemd[2373]: pulseaudio.service: Killing process 13050 (pulseaudio) with signal SIGKILL. Jun 27 09:45:10 hostname systemd[2373]: pulseaudio.service: Main process exited, code=killed, status=9/KILL Jun 27 09:45:10 hostname systemd[2373]: pulseaudio.service: Failed with result 'timeout'. Jun 27 09:45:10 hostname systemd[2373]: pulseaudio.service: Scheduled restart job, restart counter is at 7. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1880835 Title: pulse audio hangs in kernel call Status in linux package in Ubuntu: Incomplete Bug description: there is no audio device accessible any more and pulse-audio process can not be terminated in kernel log there is such a output: This makes the complete audio unstable in the laptop. I think it is started to happen when I installed Nvidia driver and there is an external monitor attached with DP audio device. [ 364.150644] INFO: task pulseaudio:2183 blocked for more than 120 seconds. [ 364.150646] Tainted: P OE 5.4.0-31-generic #35-Ubuntu [ 364.150647] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 364.150647] pulseaudio D 0 2183 2175 0x00004120 [ 364.150649] Call Trace: [ 364.150653] __schedule+0x2e3/0x740 [ 364.150655] ? dma_pte_clear_level+0x142/0x190 [ 364.150655] schedule+0x42/0xb0 [ 364.150656] schedule_timeout+0x203/0x2f0 [ 364.150657] wait_for_completion+0xb1/0x120 [ 364.150659] ? wake_up_q+0x70/0x70 [ 364.150663] fw_run_transaction+0xdc/0x110 [firewire_core] [ 364.150665] ? fw_core_handle_bus_reset+0x440/0x440 [firewire_core] [ 364.150666] ? free_iova_fast+0x18/0x30 [ 364.150667] ? close_transaction+0x110/0x110 [firewire_core] [ 364.150668] ? intel_unmap+0xd9/0x1c0 [ 364.150670] ? transmit_phy_packet_callback+0x20/0x20 [firewire_core] [ 364.150671] snd_fw_transaction+0xbc/0x110 [snd_firewire_lib] [ 364.150673] ? avc_general_get_plug_info+0x100/0x100 [snd_firewire_lib] [ 364.150674] pcr_modify+0x65/0x100 [snd_firewire_lib] [ 364.150675] cmp_connection_break+0x37/0x50 [snd_firewire_lib] [ 364.150677] snd_oxfw_stream_start_duplex+0x1ee/0x2e0 [snd_oxfw] [ 364.150678] ? wait_woken+0x80/0x80 [ 364.150679] pcm_capture_prepare+0x26/0x50 [snd_oxfw] [ 364.150682] snd_pcm_do_prepare+0x1e/0x30 [snd_pcm] [ 364.150684] snd_pcm_action_single+0x3c/0x80 [snd_pcm] [ 364.150686] snd_pcm_action_nonatomic+0x6e/0x80 [snd_pcm] [ 364.150687] snd_pcm_prepare+0x6a/0x90 [snd_pcm] [ 364.150689] snd_pcm_common_ioctl+0x28c/0xc00 [snd_pcm] [ 364.150691] snd_pcm_ioctl+0x27/0x40 [snd_pcm] [ 364.150692] do_vfs_ioctl+0x407/0x670 [ 364.150694] ? __secure_computing+0x42/0xe0 [ 364.150694] ksys_ioctl+0x67/0x90 [ 364.150695] __x64_sys_ioctl+0x1a/0x20 [ 364.150697] do_syscall_64+0x57/0x190 [ 364.150698] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 364.150699] RIP: 0033:0x7f0bbfa1a37b [ 364.150701] Code: Bad RIP value. [ 364.150701] RSP: 002b:00007ffed915d308 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 364.150702] RAX: ffffffffffffffda RBX: 00005607c7b63de0 RCX: 00007f0bbfa1a37b [ 364.150703] RDX: 0000000000000000 RSI: 0000000000004140 RDI: 000000000000006e [ 364.150703] RBP: 00005607c7b63bb0 R08: 0000000000000000 R09: 0000000000001000 [ 364.150703] R10: 0000000000000004 R11: 0000000000000202 R12: 00005607c7b63de0 [ 364.150704] R13: 00007ffed915d6f0 R14: 0000000000000000 R15: 00007ffed915d480 ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-31-generic 5.4.0-31.35 ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34 Uname: Linux 5.4.0-31-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.11-0ubuntu27 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Wed May 27 10:07:13 2020 InstallationDate: Installed on 2020-02-22 (94 days ago) InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200220) MachineType: Dell Inc. Precision 7540 ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-31-generic root=UUID=7a5890f6-2724-480a-8fa7-778d07cd929d ro quiet splash vt.handoff=7 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: Daemon not responding. RelatedPackageVersions: linux-restricted-modules-5.4.0-31-generic N/A linux-backports-modules-5.4.0-31-generic N/A linux-firmware 1.187 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 03/12/2020 dmi.bios.vendor: Dell Inc. dmi.bios.version: 1.8.2 dmi.board.name: 0T2FXT dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 10 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvr1.8.2:bd03/12/2020:svnDellInc.:pnPrecision7540:pvr:rvnDellInc.:rn0T2FXT:rvrA00:cvnDellInc.:ct10:cvr: dmi.product.family: Precision dmi.product.name: Precision 7540 dmi.product.sku: 0926 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1880835/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp